This invention relates generally to agricultural combines used in the harvesting of crops and is particularly directed to a cylinder for use in a combine in separating grain from plant residue.
A combine is an agricultural vehicle used in the harvesting of crops. The combine is typically self-propelled and is comprised of a forward header assembly and an aft drive and processing section. The header assembly typically is substantially wider than the aft portion of the combine and includes a plurality of spaced corn or row crop heads which are adapted for engaging the crops in removing the grain therefrom. The thus removed grain, in combination with crop residue such as husks in the case of corn harvesting, are then automatically delivered to the aft processing and drive portion of the combine. In addition to housing the source of propulsion, such as a diesel engine, and operator controls, the aft portion of the combine also includes a complicated threshing system for further separating the grain from the crop residue and for off-loading the thus separated grain from the combine into a transport vehicle such as a truck. The crop residue is then exhausted from an aft portion of the combine and deposited in the field being harvested.
Combines typically make use of a rotating cylinder in the early stages of grain-crop residue separation. The cylinder is typically oriented horizontally and transversely to the direction of combine travel and is adapted to receive that portion of the crop which is separated from the plant by the forward header assembly. The rotating cylinder operates in cooperation with a concave structure positioned adjacent to and below the cylinder. The cylinder-concave combination operates to separate the grain from the husk or leafy portion of the plant. The cylinder includes a first plurality of spaced raspbars around the periphery and extending the length thereof, while the concave includes a second plurality of spaced bars generally parallel to the raspbars. The crop is directed to the space between the rotating cylinder and the concave and the action of the rotating cylinder upon the crop as it is engaged by both the rotating cylinder and concave causes the grain bearing portion of the plant, i.e., the cob in corn harvesting, to become separated from the remaining portion of the plant, i.e., the leafy portion. The grain is then subjected to additional processing for further separation, while the crop residue is exhausted from the combine.
In the prior art, various problems have been encountered as the grain transits the cylinder-concave portion of the combine. For example, the impact of the cylinder upon the plant frequently results in cracking of the grain making the grain more susceptible to deterioration by moisture and attack by pests such as insects. In addition, debris such as crop residue and soil ingested by the combine is frequently deposited in and retained by the rotating cylinder. As the mass of this debris increases, out of balance operation of the cylinder occurs resulting in irregular engagement of the crop by the cylinder and degraded grain separation. Rotation of the cylinder in this out of balance condition also requires the combine operator to interrupt operation and clean out the debris within the cylinder. This condition also causes increased wear on the cylinder's bearings resulting in reduced combine reliability.
The present invention overcomes these and other limitations of the prior art by providing a solid cylinder in one embodiment, and a substantially solid, continuous cylinder in another embodiment, for use in a combine in separating grain from the remaining portion of the plant which reduces grain damage arising from impact with the cylinder, prevents cylinder out of balance operation, affords more reliable combine operation and provides increased grain handling capacity.